Digital image compression decreases the storage size of digital images. Digital image compression is particularly useful when storing or transmitting large numbers of images, or when transmitting images over network connections. A common compression method standard that many image processing systems use is the JPEG standard. JPEG compression is a lossy compression standard that trades off image quality for image size. Thus, as JPEG compression increase the amount of compression, the image quality decreases. As such, high JPEG compression can cause image artifacts that cause an image to lose significant amounts of visible detail.
To provide a balance between image quality loss and image compression, some conventional image processing systems provide a plurality of different preset compression configurations. Specifically, users may select from the preset compression configurations to obtain different amounts of compression and image quality. For example, often the preset compression configurations are based on research associated with the human psychovisual system that determines how much detail humans can see in accordance with different visual properties of images. To illustrate, when compressing an image using JPEG compression, a user can select an image quality or compression amount with corresponding preset compression configurations.
Although preset compression configurations provide some flexibility in allowing a user to modify compression amounts and image quality, such preset compression configurations have limitations. In particular, preset compression configurations often produce significant quality differences based on the content of images. For example, applying a preset compression configuration associated with a selected image compression amount can result in very different visual fidelity with significantly different storage sizes when applied to different images with different content. Similarly, applying a preset compression configuration associated with a selected image compression amount can result in very different visual fidelity for different areas within a single image based on the content in the different areas. Thus, although preset compression configurations provide some amount of flexibility and customization, preset compression configurations are not reliable for producing consistent visual fidelity, and can also result in wasted storage space and excessive loading/transfer times.
Additionally, some conventional image processing systems allow users to manually select an image quality (compression amount) when saving an image as a JPEG file. Manual selection of image quality for many images, however, can be difficult and time-consuming. More specifically, for use cases involving many images (e.g., web storage of multiple images), manually selecting the proper compression settings for each image requires significant amounts of time. On the other hand, performing batch processes by allowing a user to manually select a single preset compression configuration for a plurality of images produces inconsistent image qualities, as previously mentioned. Thus, manual selection of preset compression settings is often a significant time investment or results in inconsistent image fidelity.
These and other disadvantages may exist with respect to conventional image compression techniques.